The fight is on over a plan to build vast corridors for cars, trucks, trains--and almost everything else

To see the future of transportation in Texas, you have to drive out to the prairie north of Austin, past the sprawling plants of Dell and Samsung, to the farthest suburbs, where wild grass and cornfields nuzzle up to McMansions with their perfect green lawns. There, giant earthmovers, their wheels taller than a Texan in his boots, are ripping up the gummy, black soil to lay a 49-mile stretch of concrete tollway. State Highway 130, at a cost of $1.5 billion, is the biggest highway project under way in the U.S. today. It is also the first test in concrete for the Trans-Texas Corridor (TTC)--a radical...